The diversion of an aircraft to an airport that is different from the initial destination occurs for example in the event of failure or in the event of particularly bad weather conditions. The use of databases containing all the airports makes it difficult to choose a diversion airport, because the number of airports displayed on a navigation screen can be considerable, notably when the aircraft is flying over a continental area.
The crew must therefore take time to choose the best diversion airport in case of need. Various criteria are involved in the choice of an airport, aircraft criteria (runways, radio beacons, weather, etc.) but also criteria relating to the passengers or to the management of airplane failures (possible maintenance, delay in routing parts, availability of hangers, hotel network, medical and police resources, charges, opening/closure times of the airport or of the air terminal etc.). The crew can contact its company, which will propose the airport to which the airplane may be diverted according to its perception of the problem, which can take time if the aircraft is flying over an area where communications are of poor quality between the flight deck and the ground. Private aviation does not offer the assistance of a ground crew for the pilots in the same way as airlines do (also called air operators). Hereinafter in this document, the term “air company” or “company” will be used to mean an organization operating an aircraft.
When the time factor becomes predominant for being diverted, the crew can choose, by agreement with air traffic control, an airport that may then prove problematic, for example: no possibility of taking off again and no hotel for the passengers. A typical example of this situation is as follows: a failure has occurred on an engine of a 777 type aircraft in flight AF267 from Seoul to Paris. The aircraft has had to make an emergency landing at Irkoutz in Siberia. The two hundred passengers and the crew members waited there for another aircraft of the same type to come and fetch them from Paris. They finally arrived in Paris but will have taken close to forty hours to make the journey from Seoul to Paris. In some cases, the crew does not necessarily have the time to contact in advance its company's flight tracking service, or else could not do so because of a failure on board the aircraft. The flight tracking service (also called dispatch) is a service on the ground responsible for assisting a crew in taking decisions concerning in-flight operations.
On board flight management systems (FMS) are known that are computers determining the geometry of the 4-dimensional profile (3 dimensions and time-speed profile) and proposing to the pilot or sending to the automatic pilot guidance instructions for following this profile. FIG. 1 represents a flight management system according to the known art that has the following functions described in the ARINC 702A standard (Advanced Flight Management Computer System). They normally handle all or some of the functions of:
navigation LOCNAV 170 for optimally locating the aircraft according to satellite geolocation means (for example GPS or GALILEO), terrestrial geolocation means (for example: VOR, DME or NDB) or onboard geolocation means (for example: inertial units or onboard computers called “air data computers”);
flight plan FPLN 110 for inputting geographic elements forming the outline of the route to be followed (departure and arrival airports, diversion airports, departure and arrival procedures, waypoints, airways);
navigation database NAV_DB 130 for constructing geographic routes and procedures from data included in the databases (points, beacons, interceptor or altitude legs, etc.) and for choosing the terrestrial beacons for the LOCNAV function. This database also includes objects created by the crew, in particular the airports and runways (called pilot database);
performance database PRF_DB 150 containing the aerodynamic and engine parameters of the aircraft;
lateral trajectory TRAJ 120 for constructing a continuous trajectory from the points of the flight plan, observing airplane performance characteristics, passenger comfort and containment constraints (called RNP);
predictions PRED 140 for constructing an optimized profile on the lateral trajectory (altitude, time, fuel and speed profile) and taking into account weather parameters (wind, temperature, atmospheric pressure);
guidance GUID 190 for servocontrolling the aircraft in the lateral and vertical planes on its trajectory in 3 dimensions, while observing the setpoint speeds and reducing the engine effects and for sending guidance instructions to an automatic pilot 193;
digital data link DATALINK 180 for communicating with the air traffic control centres (ATC function) 191 and the other aircraft, and with the company (AOC function) 191 in order to communicate the updates to the parameters relating to the alternative airports.
These different functions are accessible to the pilot via an interface 194.
The functions that can be accessed via an FMS are insufficient to allow a relevant choice of a diversion airport. On the one hand, the content of the navigation databases of the flight management system is standardized internationally (Arinc 424). These navigation databases do not contain company data other than regular routes (company routes), this information being insufficient for a quick decision concerning a diversion airport. On the other hand, these databases are static and are updated only every twenty-eight days whereas certain airport characteristics require more frequent updates.
Also known from U.S. Pat. No. 5,526,265 is a system presenting a list of airports closest to the position of the aircraft, these airports being derived from the navigation database of the flight management system by calculating a set of information for each of them (distance, estimated time of arrival, fuel consumption). This airport selection may have little relevance when the aircraft is crossing a region with a high density of airports.